Contact printing method and apparatus with electrostatic means for film registration

ABSTRACT

A method and apparatus for contact printing of continuous strips of film in which the image on the transparent master film is exposed with the light-sensitive negative film while the film strips are in an exposure zone. The film strips are maintained in precise registry through electrostatic devices which produce opposite charges on the two strips, causing them to attract and strongly adhere to one another, thereby preventing relative transverse, lateral and longitudinal movement during exposure. An alternative form of the invention providing for using a master having a substantially smaller width than the duplicate, and printing a plurality of master strips on the duplicate in sideby-side relation.

United States Patent Beispel [451 Mar. 21, 1972 CONTACT PRINTING METHOD AND APPARATUS WITH ELECTROSTATIC MEANS FOR FILM REGISTRATION Inventor: Robert Beispel, Westlake Village, Calif.

Assignee: Extek Microsystems, Inc., Van Nuys, Calif.

Filed: Dec. 18, 1969 Appl. No.: 886,171

U.S. Cl ..355/l2, 355/16, 355/17, 355/50, 355/99, 355/103, 355/132 Int. Cl. ..G03g 15/00 Field oiSearch ..355/16, l7,31,50,99, 103,

References Cited UNITED STATES PATENTS 3/1967 Olden ..355/16 X 'iilllll 3,148,600 9/1964 Bain ..355/l6 X Primary Examiner-Samuel S. Matthews Assistant ExaminerRichard A. Wintercorn Attorney-Nilsson, Robbins, Wills & Berliner [5 7] ABSTRACT A method and apparatus for contact printing of continuous strips of film in which the image on the transparent master film is exposed with the light-sensitive negative film while the film strips are in an exposure zone. The film strips are maintained in precise registry through electrostatic devices which produce opposite charges on the two strips, causing them to attract and strongly adhere to one another, thereby preventing relative transverse, lateral and longitudinal movement during exposure. An alternative form of the invention providing for using a master having a substantially smaller width than the duplicate, and printing a plurality of master strips on the duplicate in side-by-side relation.

23 Claims, 4 Drawing Figures CONTACT PRINTING METHOD AND APPARATUS WITH ELECTROSTATIC MEANS FOR FILM REGISTRATION BACKGROUND OF THE INVENTION AND PRIOR ART The process for transferring information from an imagebearing transparent film to an unexposed light-sensitive film is generally known as printing. In the printing process, two strips of film are brought together in emulsion-to-emulsion contact over a portion of their length and light is passed through the strips when they are in such juxtaposed relationship. Such exposure of the light-sensitive duplicate effects the transfer of information from the master to the duplicate. For purposes of convenience and description, the present application is described in relation to film media in which such term is used to mean a positive or negative, clear, transparent, continuous roll, strip or web of dielectric material which may be either exposed or unexposed. The term master is used to mean an exposed image or character bearing film, either positive or negative, which may be an original I or exposed duplicate. The term duplicate is used to identify duplicate stock or work stock which terms are considered interchangeable and are used to mean an initially unexposed, light-sensitive film to which an image is transferred during operation of the contact printing apparatus.

In the prior art, such as devices presently used in the motion picture industry, rolls or strips of film have been of the drum or roller type wherein the films are wound around a portion of a drum to bring the emulsions in face-to-face contact. Such arrangements are not satisfactory, however, because the films are exposed in a non-planar zone, i.e., around the arc of the roller whichcauses optical distortion resulting in a loss of resolution in the duplicate. Moreover, problems of synchronization and registration are aggravated because the duplicate and master films travel over different distances, because of the difference in their radial spacing from the center of the roller which causes slippage, misregistration, and optical distortion. Another difficulty has been roller tension which causes the films to stretch, curl and break.

To overcome these difficulties, various apparatus has been suggested for contact printing of rolls of film in which the films are maintained in registration as they pass simultaneously through a light exposure zone by the application of a vacuum for compressing the film through the atmospheric pressure or by the application of high pressure air which forces the film strip portions in contact. One example of the vacuum type means and method is disclosed in U.S. Pat. No. 3,468,606 issued Sept. 23, 1969, to Robert Beispel and Margery S. Wolf. An example of a high pressure fluid type of device is disclosed in U.S. Pat. No. 3,161,120, issued Dec. 15, 1964, to Robert F. Kiddle and Norman R. Timares. While these systems function satisfactorily under normal conditions, they suffer the disadvantage of requiring complex fluid pressure systems including motors, pumps, regulators, pressure switches, solenoid valves, air tanks, filters, and the like. Not only do the fluid systems increase the complexity and therefore the initial cost of the can:

tact printing apparatus, but reliability and maintenance are not always satisfactory.

Moreover, there are as a practical matter, limits to the pressure contact which can be obtained through the fluid pressurizing systems which may affect the compressive or adherence force which provides the registration. Such registration problems become particularly acute where high reductions in image size, common to microfilm and microfiche, place great demands on optical resolution during printing. Aggravating the problems of fine resolution is the desired speeds at which the duplicate film may be printed to keep pace with the film produced by computer film output devices.

SUMMARY OF THE INVENTION 4 In light of the above-discussed disadvantages of prior art systems, it is a general object of the present invention to provide means and method for contact printing from a transparent image-bearing master film to a duplicate film by moving the film strips through a planar exposure zone and maintaining them in registration by electrostatically attracting the film strips as they are moved from supply to takeup reels. Charging of the film strips may involve application of corona discharge techniques or other means and methods for applying electrostatically opposite charges to the two strips.

It is another object of the present invention to provide means and method for contact printing of rolls of film from a master to a duplicate while maintaining the film in registration as it is passed through an exposure zone by electrostatically positively charging one of the film rolls and negatively charging the other of the film rolls so as to produce an attraction therebetween and tight strong adherence so as to prevent transverse, lateral and/or longitudinal relative movement between lengths of the film rolls being exposed.

It is still another object of the present invention to provide an apparatus of the above-described type wherein the electrostatic charging device comprises a pair of conductive transparent plates positioned on opposite sides of the film strips and an exposure or light source positioned above one of such plates for exposing the film strips while the strips are under the influence of the electrostatic device.

Generally, the present invention relates to means and method for printing a continuous strip of dielectric material from a transparent master strip of dielectric material, comprising a frame supporting a pair of supply reels on which the master and duplicate strips are initially wound, a pair of takeup reels on which the master and duplicate strips are finally wound, means for moving the strips from the supply to the takeup reels, means for exposing the master and duplicate in a planar zone disposed between the reels, and means for electrostatically charging at least one of the strips so as to cause attraction and strong adherence between the strips during movement thereof through the exposure zone so as to prevent relative movement therebetween. In one embodiment of the present invention, the means for exposing the master and duplicate is positioned above the electrostatic means for charging the strips which comprises a pair of conductive transparent plates which effect the electrostatic attraction between the strips.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, there is diagrammatically shown an exemplary embodiment of an apparatus for contact printing from an image-bearing transparent continuous master strip of film to a light-sensitive continuous duplicate film strip. Generally, such apparatus comprises a frame (not shown) sup porting a pair of supply reels 21, 22 around which the master and duplicate film strips are initially wound and a pair of takeup reels 23, 24 on which the film is finally wound. Such reels are entirely conventional, the takeup reels being-driven and a suitable brake provided for the supply reels.

Means 30 is provided for isolating the master and negative strips from tension produced by the supply and takeup reels. In the exemplary embodiment, such means may include a pair of idler rollers 31, a pair of drive rollers 32, and a second pair of idler rollers 33. The film strips are fed through the roller pairs so that large oppositely directed loops or bights are formed between drive roller pair 32 and the second pair of idler rollers 33. Means 34 for one of the loops is provided to sense the length of such loops (between, for example, certain limits) to control the speed of drive roller pair 32 thereby increasing or decreasing the loop lengths of both strips as required. Such means may be electromechanical or electrooptical as is well known in the art. Identical means 35, including idler roller pair 36, drive roller pair 37, second idler roller pair 38 and servo-mechanism control unit 39, is provided to maintain a loop in each of the film strips prior to takeup.

Means 40 is provided for moving said strips from the supply reels 21, 22 to the takeup reels 23, 24. In the illustrated embodiment, such means comprises a pair of metering rollers or capstans 41 driven by a motor (not shown) which may be adjustable to the desired speed of film movement. As will be apparent, drive roller pairs 32 will be driven at a speed equal to the speed of capstans 41, the servo-mechanism control units 34 and 39 functioning only to compensate for speed differentials between the capstans and drive roller pairs.

Means 45 is positioned between the supply and takeup reels for exposing said master and duplicate in a planar exposure zone. Said means will be compatible with the type of film being used in the printing operation. For example, where the duplicate light-sensitive material is diazo sensitized, a mercury lamp 46, or plurality of such lamps, will be employed. It will be understood that the exposed duplicate film on reel 24 may be later developed in known manner appropriate to the particular emulsion used; alternatively, suitable developing means may be incorporated immediately downstream of the tension isolating means 35, but such means are not here shown since their details are well known in the art and form no part of the present invention.

The contact printing apparatus also includes means 50 for electrostatically charging at least one of said film strips. Such means in the exemplary embodiment of FIG. 1 comprises a pair of electrostatic charging units 51, 52, which may be of the corona discharge type, including housing 53, 54 in which are disposed fine wires 55, 56, respectively. A source of DC voltage (not shown) in the range of 4,0008,000 volts and a current of a few microamperes is provided. The charging units 51, 52 are positioned on opposite sides of the film strips which have been brought into close physical proximity by idler roller pair 33. As is known in the art, the charging units will produce opposite electrostatic surface charges on the film strips, which in accordance with Coulomb's law, will cause attraction and strong adherence between the two strips.

The apparatus of FIG. 1 also includes means 60 for laterally aligning the master and duplicate strips prior to entry into the planar exposure zone. In this embodiment, such means comprises two pair of rollers 61, 62 disposed with their axes of rotation generally perpendicular to the plane of the master and duplicate strips and on opposite sides of the strips so as to contact the edges thereof and maintain the lateral alignment. Such lateral aligning rollers also prevent tracking of the film and therefore insure proper registration for exposure.

Positioned between the charging units 51, 52 and the exposure means 45 is means for mechanically forcing and expelling air from between the strips which in the exemplary embodiment comprise a pair of rollers 65, preferably of dielectric material such as rubber or equivalent, in pressure contact with the adhered strips of film. Such rollers will press the air out from between the film strips so as to prevent optical distortion which might otherwise result, as from the fact that the index of refraction of any air trapped between the two film strips is different from that of the strips themselves.

It is important to note that the master and duplicate film strip portions in the exposure zone are supported by insulated rollers disposed exteriorly of the exposure zone and are not carried by any belt, or the like. Accordingly, there is no necessity for adhering the film strip to a belt which involves additional problems of electrostatic attraction as well as problems of splitting the strips away from the belt. Furthermore, elimination of a carrier or transport device for the film strips while in the exposure zone minimizes the problems of scratching or rubbing between the film strips and such carrier,

which may deleteriously affect the clarity and legibility and therefore the life of the master as well as the duplicate. Problems of reflection which may affect the quality of the printing are also avoided by eliminating an external carrier or transport device when both the master and duplicate films are transparent.

Turning now to FIG.,2, a modification of the means for. applying an electrostatic charge to the master and duplicate films is disclosed. In this embodiment, such modified means comprises a pair of plates 71, 72, at least one of which, as 71, is transparent, the plates have electrically conductive surfaces, and may be of glass with a thin, transparent, metal layer applied to the glass surface by known techniques such as vacuum or vapor deposition, or sputtering. The conductive layers on the glass may be connected to a source of DC voltage so that one of such plates provide a positive charge on one of the strips while the other plate provides a negative charge on the other strip. In contradistinction to the first discussed embodiment, the present embodiment provides for exposure means which may comprise a lamp 73 and housing 74 which is positioned immediately adjacent the charging plates. It will be appreciated that in the first embodiment, the electrostatic charge is applied to the strips prior to their entrance into the exposure zone. Under some conditions a portion of such charge may leak from the strips and thus, depending upon the charge deposited, the length of the exposure zone, and the speed of the film, the force of electrostatic attraction may vary to a greater or lesser extent. In the present embodiment, of course, the electrostatic force of attraction is at a maximum during the exposure.

With reference now to FIGS. 3 and 4, there is shown a modified apparatus for contact printing of continuous strips of film and adapted for a specialized application. Specifically, the apparatus of this embodiment is adopted for printing of successive predetermined lengths of the master of substantially less width so that multiple lengths of the master may be printed on a single predetermined length of the duplicate. For example, three 35 mm. master strips may be printed in sideby-side relation on a mm. microfiche duplicate. In the embodiment shown, the apparatus includes supply and takeup reels or rollers 80, 81 and the film is moved in steps so that successive predetermined lengths of the master will be presented in the exposure zone. The duplicate film is also wound on reels (not shown) and is selectively movable in steps into the exposure zone. The reels 80, 81 are mounted on shafts 82, 83, respectively, and are adapted to be selectively laterally displaced by means, which may be manual, to successive lateral positions, as shown in FIG. 4, in synchronization with the step movements of the predetermined lengths of the master. It will be understood that the duplicate strip remains stationary while the master strip is advanced and moved laterally for three successive exposures (in the case of a 35 mm. master and a 105 mm. duplicate) or other appropriate number of such exposures.

Electrostatic means for selectively attracting and adhering the master and duplicate films is provided which may comprise a pair of plates 85, 86, at least one of which, as 85, is transparent, the plates have electrically conductive surfaces which are connected to a suitable source of DC voltage. Mounted above the plates 85, 86 is a light source 87 which transmits light for exposure of the light-sensitive duplicate through the transparent plate 85.

In operation, a length of the image-bearing master is disposed in a first lateral position adjacent one edge of the duplicate and the electrostatic means is actuated so as to attract and adhere the master to the duplicate whereupon the light source is activated to effect exposure. The electrostatic charge on the films is then removed, permitting the master film strip to be moved away from the duplicate film strip, which remains stationary. The operator then shifts the reels 80, 81 on shafts 82, 83 and concurrently advances the master through a predetermined length of film to the position as shown in FIG. 4 where the electrostatic means is again actuated to register the master and duplicate. The light source is then energized, exposing the next portion of the duplicate to the newly positioned portion of the master. This sequence of operations is then followed for a third exposure (in the case of a 35 mm. master and a 105 mm. duplicate), the duplicate film of course remaining stationary throughout the cycle of three exposures.

The method for printing a duplicate continuous strip of film from a master transparent continuous strip of such dielectric material generally comprises the movement of the master and duplicate strips through an exposure zone, electrostatically charging at least one of the strips, initially physically bringing the strips in sufficiently close proximity so that the opposite charges on the strips will attract the strips to one another and maintain adherence therebetween to prevent movement while moving through the exposure zone, and exposing the master and duplicate in such zone. It will therefore be seen that the method and apparatus of the present invention accomplishes the objects set forth above and provides for the efficient, rapid, contact printing from a transparent master film to a duplicate film strip to effect a transfer of information. Other modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described in relation to the exemplary embodiments discussed.

I claim:

1. An apparatus for printing a duplicate continuous strip of dielectric material from a master continuous strip of dielectric material comprising:

a duplicate continuous strip of dielectric material having a surface sensitive to electromagnetic radiation,

a master continuous strip of dielectric material bearing information to be duplicated,

supply means for supplying said master and duplicate strips,

means for moving said strips,

takeup means for taking up said master and duplicate strips,

means for exposing said master and duplicate strips in a planar exposure zone disposed between said supply and takeup means, and

means for electrostatically charging the entire surface of at least one of said strips so as to cause attraction and adherence between said master strip and duplicate strip sensitive surface during movement of said strips through said exposure zone to prevent relative movement therebetween.

2. An apparatus for printing a duplicate continuous strip of dielectric material from a master continuous transparent strip ofdielectric material comprising:

supply means for supplying said master and duplicate strips;

means for moving said strips;

takeup means for taking up said master and duplicate strips;

means for exposing said master and duplicate strips in a planar exposure zone disposed between said supply and takeup means;

means for electrostatically charging at least one of said strips so as to cause attraction and adherence between said master and duplicate strips during movement of said strips through the exposure zone to prevent relative movement therebetween; and

means positioned between said charging means and said exposure zone for mechanically forcing and expelling air from between said strips;

said supply and takeup means being positioned exteriorly of said exposure zone, said master and duplicate being unsupported in said exposure zone.

3. The apparatus of claim 2 wherein said air expulsion means comprises a pair of insulated rollers in pressure contact with said adhered strips.

4. The apparatus of claim 2 additionally including means for laterally aligning said strips.

5. The apparatus of claim 4 wherein said aligning means comprises at least one pair of insulated rollers disposed with their axes of rotation generally perpendicular to the plane of said strips, on opposite sides of said adhered strips, and in contact with the edges of said strips.

6. An apparatus for printing a duplicate continuous strip of dielectric material from a master continuous transparent strip of dielectric material comprising:

supply means for supplying said master and duplicate strips;

means for moving said strips;

takeup means for taking up said master and duplicate strips;

means for exposing said master and duplicate strips in a planar exposure zone disposed between said supply and takeup means; and

means for electrostatically charging at least one of said strips so as to cause attraction and adherence between said master and duplicate strips during movement of said strips through the exposure zone to prevent relative movement therebetween;

said supply and takeup means being positioned exteriorly of said exposure zone, said master and duplicate strips being unsupported in said exposure zone;

said means for electrostatically charging said strips comprising a pair of plates having facing electrically conductive surfaces positioned on opposite sides of said strips and in said exposure zone, the plate between the strips and the exposing means being transparent, one of said plates positively charging one of said strips and the other of said plates negatively charging the other of said strips.

7. The apparatus of claim 6 wherein said plates are metallic coated glass.

8. An apparatus for printing a duplicate continuous strip of dielectric material from a master continuous transparent strip of dielectric material comprising:

supply means for supplying said master and duplicate strips;

means for moving said strips;

takeup means for taking up said master and duplicate strips;

means for exposing said master and duplicate strips in a planar exposure zone disposed between said supply and takeup means; means for electrostatically charging at least one of said strips so as to cause attraction and adherence between said master and duplicate strips during movement of said strips through the exposure zone to prevent relative movement therebetween; and means for isolating said strips while in said exposure zone from tension produced by said supply and takeup means;

said supply and takeup means being positioned exteriorly of said exposure zone, said master and duplicate strips being unsupported in said exposure zone.

9. The apparatus of claim 6 wherein said master strip has a width substantially less than said duplicate strip and said apparatus additionally includes means for laterally and longitudinally displacing said master strip relative to said duplicate strip and means for selectively charging said strips so that predetermined lengths of said master strip may be adhered to laterally spaced portions of said duplicate strip of substantially the same predetermined length.

10. An apparatus for photographically printing a duplicate continuous strip of film from a master transparent continuous strip of film comprising:

spaced apart supply and takeup means for each of said strips;

means for exposing said film strips as they are passed through a zone; two pairs of rollers adjacent each end of said exposure zone, one of said pairs of rollers including a roller being driven for pulling said film strips through said exposure zone and the other of said pairs of rollers pressure contact with said film strips for expelling air from therebetween; and

electrostatic means for positively charging one of said film strips and negatively charging the other of said film strips so that said strips will be strongly attracted together to prevent relative movement therebetween;

said electrostatic means comprising a pair of conductively coated glass plates positioned on opposite sides of said film strips and a source of electrical energy connected to said plate coatings to produce electrostatic charges on said plates.

11. A method for printing a duplicate continuous strip of dielectric material from a master continuous strip of dielectric material, comprising:

moving a master strip bearing information to be duplicated and a duplicate strip having a surface sensitive to electromagnetic radiation through an exposure zone; initially physically bringing said master strip and sensitive surface of said duplicate strip in close proximity;

electrostatically charging the entire surface of at least one of said strips so that opposite charges on said strips will cause attraction and maintain adherence therebetween to prevent relative movement therebetween while moving through said exposure zone; and

exposing said master and duplicate in said exposure zone.

12. A method for printing a duplicate continuous strip of dielectric material from a master transparent continuous strip of dielectric material, comprising:

moving said master and duplicate strips through an exposure zone;

initially physically bringing said strips in close proximity;

electrostatically charging at least one of said strips so that opposite charges on said strips will cause attraction and maintain adherence therebetween to prevent relative movement therebetween while moving through said exposure zone;

exposing said master and duplicate in said exposure zone;

and

mechanically forcing and expelling air from between said strips subsequent to electrostatic charging of said strips and prior to movement into said exposure zone.

13. The method of claim 12 additionally including the step of laterally aligning said strips prior to electrostatically charging.

14. The method of claim 11 wherein said steps of electrostatically charging and exposing said master and duplicate are performed simultaneously.

15. The method of claim 14 wherein said master strip is moved in steps and is laterally displaced relative to said duplicate strip on each successive step of longitudinal movement of said master strip so that successive lengths of said master may be exposed to said duplicate in multiple laterally spaced positions, thereby transferring the information carried by several predetermined lengths of the master strip to a single equal length ofa wider duplicate strip.

16. An apparatus for printing a duplicate continuous strip of dielectric material from a master continuous transparent strip of dielectric material comprising:

supply means for supplying said master and duplicate strips;

means for moving said strips; takeup means for taking up said master and duplicate strips; means for exposing said master and duplicate strips in a planar exposure zone disposed between said supply and takeup means;

means for electrostatically charging at least one of said strips so as to cause attraction and adherence between said master and duplicate strips during movement of said strips through the exposure zone to prevent relative movement therebetween; and

means positioned prior to said exposure zone for mechanically forcing and expelling air from between said electrostatically charged strips;

said supply and takeup means being positioned exteriorly of said exposure zone, said master and duplicate being unsupported in said exposure zone.

17. The apparatus of claim 16 wherein said air expulsion means comprises a pair of insulated rollers in pressure contact with said adhered strips.

18. The apparatus of claim 16 additionally including means for laterally aligning said strips.

19. The apparatus of claim 18 wherein said aligning means comprises at least one roller disposed with its axis of rotation generally perpendicular to the plane of said strips and in contact with an edge of said strips.

20. A method for printing a duplicate continuous strip of dielectric material from a master transparent continuous strip of dielectric material, comprising:

moving said master and duplicate strips through an exposure zone;

initially physically bringing said strips in close proximity;

electrostatically charging at least one of said strips so that opposite charges on said strips will cause attraction and maintain adherence therebetween to prevent relative movement therebetween while moving through said exposure zone;

exposing said master and duplicate in said exposure zone;

and

mechanically forcing and expelling air from between said strips prior to movement into said exposure zone.

21. The method of claim 20 additionally including the step of laterally aligning said strips prior to electrostatically chargmg.

22. A method for printing a duplicate continuous strip of dielectric material from a master transparent continuous strip of dielectric material, comprising:

moving said master and duplicate strips through an exposure zone;

initially physically bringing said strips in close proximity;

electrostatically charging at least one of said strips so that opposite charges on said strips will cause attraction and maintain adherence therebetween to prevent relative movement therebetween while moving through said exposure zone;

exposing said master and duplicate in said exposure zone;

and

mechanically forcing and expelling air from between said electrostatically attracted strips prior to movement into said exposure zone.

23. A method for printing a duplicate continuous strip of dielectric material from a plurality of lengths of master transparent continuous strip of dielectric material, said duplicate strip being at least as wide as the total widths of said plurality of master strips, comprising:

physically bringing in close proximity to said duplicate strip said plurality of lengths of master strip in multiple laterally spaced positions on said duplicate strip; electrostatically charging said master strips or duplicate strip so that opposite charges on said strips will cause attraction and maintain adherence therebetween to prevent relative movement therebetween while moving through said exposure zone; moving said master and said duplicate strips in said exposure zone thereby transferring the information carried by said plurality of master strips to a single duplicate strip. 

1. An apparatus for printing a duplicate continuous strip of dielectric material from a master continuous strip of dielectric material comprising: a duplicate continuous strip of dielectric material having a surface sensitive to electromagnetic radiation, A master continuous strip of dielectric material bearing information to be duplicated, supply means for supplying said master and duplicate strips, means for moving said strips, takeup means for taking up said master and duplicate strips, means for exposing said master and duplicate strips in a planar exposure zone disposed between said supply and takeup means, and means for electrostatically charging the entire surface of at least one of said strips so as to cause attraction and adherence between said master strip and duplicate strip sensitive surface during movement of said strips through said exposure zone to prevent relative movement therebetween.
 2. An apparatus for printing a duplicate continuous strip of dielectric material from a master continuous transparent strip of dielectric material comprising: supply means for supplying said master and duplicate strips; means for moving said strips; takeup means for taking up said master and duplicate strips; means for exposing said master and duplicate strips in a planar exposure zone disposed between said supply and takeup means; means for electrostatically charging at least one of said strips so as to cause attraction and adherence between said master and duplicate strips during movement of said strips through the exposure zone to prevent relative movement therebetween; and means positioned between said charging means and said exposure zone for mechanically forcing and expelling air from between said strips; said supply and takeup means being positioned exteriorly of said exposure zone, said master and duplicate being unsupported in said exposure zone.
 3. The apparatus of claim 2 wherein said air expulsion means comprises a pair of insulated rollers in pressure contact with said adhered strips.
 4. The apparatus of claim 2 additionally including means for laterally aligning said strips.
 5. The apparatus of claim 4 wherein said aligning means comprises at least one pair of insulated rollers disposed with their axes of rotation generally perpendicular to the plane of said strips, on opposite sides of said adhered strips, and in contact with the edges of said strips.
 6. An apparatus for printing a duplicate continuous strip of dielectric material from a master continuous transparent strip of dielectric material comprising: supply means for supplying said master and duplicate strips; means for moving said strips; takeup means for taking up said master and duplicate strips; means for exposing said master and duplicate strips in a planar exposure zone disposed between said supply and takeup means; and means for electrostatically charging at least one of said strips so as to cause attraction and adherence between said master and duplicate strips during movement of said strips through the exposure zone to prevent relative movement therebetween; said supply and takeup means being positioned exteriorly of said exposure zone, said master and duplicate strips being unsupported in said exposure zone; said means for electrostatically charging said strips comprising a pair of plates having facing electrically conductive surfaces positioned on opposite sides of said strips and in said exposure zone, the plate between the strips and the exposing means being transparent, one of said plates positively charging one of said strips and the other of said plates negatively charging the other of said strips.
 7. The apparatus of claim 6 wherein said plates are metallic coated glass.
 8. An apparatus for printing a duplicate continuous strip of dielectric material from a master continuous transparent strip of dielectric material comprising: supply means for supplying said master and duplicate strips; means for moving said strips; takeup means for taking up said master and duplicate strips; means for exposing said master and duplicate strips in a planar exposure zone disposed between said supply and takeup means; means for electrostatically charging at least one of said strips so as to cause attraction and adherence between said master and duplicate strips during movement of said strips through the exposure zone to prevent relative movement therebetween; and means for isolating said strips while in said exposure zone from tension produced by said supply and takeup means; said supply and takeup means being positioned exteriorly of said exposure zone, said master and duplicate strips being unsupported in said exposure zone.
 9. The apparatus of claim 6 wherein said master strip has a width substantially less than said duplicate strip and said apparatus additionally includes means for laterally and longitudinally displacing said master strip relative to said duplicate strip and means for selectively charging said strips so that predetermined lengths of said master strip may be adhered to laterally spaced portions of said duplicate strip of substantially the same predetermined length.
 10. An apparatus for photographically printing a duplicate continuous strip of film from a master transparent continuous strip of film comprising: spaced apart supply and takeup means for each of said strips; means for exposing said film strips as they are passed through a zone; two pairs of rollers adjacent each end of said exposure zone, one of said pairs of rollers including a roller being driven for pulling said film strips through said exposure zone and the other of said pairs of rollers pressure contact with said film strips for expelling air from therebetween; and electrostatic means for positively charging one of said film strips and negatively charging the other of said film strips so that said strips will be strongly attracted together to prevent relative movement therebetween; said electrostatic means comprising a pair of conductively coated glass plates positioned on opposite sides of said film strips and a source of electrical energy connected to said plate coatings to produce electrostatic charges on said plates.
 11. A method for printing a duplicate continuous strip of dielectric material from a master continuous strip of dielectric material, comprising: moving a master strip bearing information to be duplicated and a duplicate strip having a surface sensitive to electromagnetic radiation through an exposure zone; initially physically bringing said master strip and sensitive surface of said duplicate strip in close proximity; electrostatically charging the entire surface of at least one of said strips so that opposite charges on said strips will cause attraction and maintain adherence therebetween to prevent relative movement therebetween while moving through said exposure zone; and exposing said master and duplicate in said exposure zone.
 12. A method for printing a duplicate continuous strip of dielectric material from a master transparent continuous strip of dielectric material, comprising: moving said master and duplicate strips through an exposure zone; initially physically bringing said strips in close proximity; electrostatically charging at least one of said strips so that opposite charges on said strips will cause attraction and maintain adherence therebetween to prevent relative movement therebetween while moving through said exposure zone; exposing said master and duplicate in said exposure zone; and mechanically forcing and expelling air from between said strips subsequent to electrostatic charging of said strips and prior to movement into said exposure zone.
 13. The method of claim 12 additionally including the step of laterally aligning said strips prior to electrostatically charging.
 14. The method of claim 11 wherein said steps of electrostatically charging and exposing said master and duplicate are performed simultaneously.
 15. The method of claim 14 wherein said master strip is moved in steps and is laterally displaced relative to said duplicate strip on each succeSsive step of longitudinal movement of said master strip so that successive lengths of said master may be exposed to said duplicate in multiple laterally spaced positions, thereby transferring the information carried by several predetermined lengths of the master strip to a single equal length of a wider duplicate strip.
 16. An apparatus for printing a duplicate continuous strip of dielectric material from a master continuous transparent strip of dielectric material comprising: supply means for supplying said master and duplicate strips; means for moving said strips; takeup means for taking up said master and duplicate strips; means for exposing said master and duplicate strips in a planar exposure zone disposed between said supply and takeup means; means for electrostatically charging at least one of said strips so as to cause attraction and adherence between said master and duplicate strips during movement of said strips through the exposure zone to prevent relative movement therebetween; and means positioned prior to said exposure zone for mechanically forcing and expelling air from between said electrostatically charged strips; said supply and takeup means being positioned exteriorly of said exposure zone, said master and duplicate being unsupported in said exposure zone.
 17. The apparatus of claim 16 wherein said air expulsion means comprises a pair of insulated rollers in pressure contact with said adhered strips.
 18. The apparatus of claim 16 additionally including means for laterally aligning said strips.
 19. The apparatus of claim 18 wherein said aligning means comprises at least one roller disposed with its axis of rotation generally perpendicular to the plane of said strips and in contact with an edge of said strips.
 20. A method for printing a duplicate continuous strip of dielectric material from a master transparent continuous strip of dielectric material, comprising: moving said master and duplicate strips through an exposure zone; initially physically bringing said strips in close proximity; electrostatically charging at least one of said strips so that opposite charges on said strips will cause attraction and maintain adherence therebetween to prevent relative movement therebetween while moving through said exposure zone; exposing said master and duplicate in said exposure zone; and mechanically forcing and expelling air from between said strips prior to movement into said exposure zone.
 21. The method of claim 20 additionally including the step of laterally aligning said strips prior to electrostatically charging.
 22. A method for printing a duplicate continuous strip of dielectric material from a master transparent continuous strip of dielectric material, comprising: moving said master and duplicate strips through an exposure zone; initially physically bringing said strips in close proximity; electrostatically charging at least one of said strips so that opposite charges on said strips will cause attraction and maintain adherence therebetween to prevent relative movement therebetween while moving through said exposure zone; exposing said master and duplicate in said exposure zone; and mechanically forcing and expelling air from between said electrostatically attracted strips prior to movement into said exposure zone.
 23. A method for printing a duplicate continuous strip of dielectric material from a plurality of lengths of master transparent continuous strip of dielectric material, said duplicate strip being at least as wide as the total widths of said plurality of master strips, comprising: physically bringing in close proximity to said duplicate strip said plurality of lengths of master strip in multiple laterally spaced positions on said duplicate strip; electrostatically charging said master strips or duplicate strip so that opposite charges on said strips will cause attraction and maintain adherence therebetween to prevent relAtive movement therebetween while moving through said exposure zone; moving said master and said duplicate strips in said exposure zone thereby transferring the information carried by said plurality of master strips to a single duplicate strip. 